I'm documenting a block of computer code and would like to make it clear and concise. I'm describing a function that populates a field on a user input screen. Here's my best shot but it still seems confusing because the 'in the', 'on the', 'for a' seem like a lot of prepositions for one sentence.
This function returns the WINGNUT_SELLER_CODE that appears in the 'Vendor' field on the 'THREADED_NUTS' screen for a given NUT_ID.
 How can I rewrite this to make it easier to understand?
 What about 'that appears' vs. 'which appears' when should I use 'that' and 'which' ?